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authorWim <wim@42.be>2021-10-16 23:11:32 +0200
committerWim <wim@42.be>2021-10-16 23:23:24 +0200
commit20f6c05ec50739d31f4dbe9fde0d223f2c43f6e8 (patch)
tree230edca06449a8d1755f08aabf45a03e07e6f17c /vendor/github.com/minio/minio-go/v7/api-get-object.go
parent57fce93af7f64f025cec6f3ed6088163086bc9fe (diff)
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Update vendor
Diffstat (limited to 'vendor/github.com/minio/minio-go/v7/api-get-object.go')
-rw-r--r--vendor/github.com/minio/minio-go/v7/api-get-object.go681
1 files changed, 681 insertions, 0 deletions
diff --git a/vendor/github.com/minio/minio-go/v7/api-get-object.go b/vendor/github.com/minio/minio-go/v7/api-get-object.go
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+++ b/vendor/github.com/minio/minio-go/v7/api-get-object.go
@@ -0,0 +1,681 @@
+/*
+ * MinIO Go Library for Amazon S3 Compatible Cloud Storage
+ * Copyright 2015-2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package minio
+
+import (
+ "context"
+ "errors"
+ "fmt"
+ "io"
+ "net/http"
+ "net/url"
+ "sync"
+
+ "github.com/minio/minio-go/v7/pkg/s3utils"
+)
+
+// GetObject wrapper function that accepts a request context
+func (c Client) GetObject(ctx context.Context, bucketName, objectName string, opts GetObjectOptions) (*Object, error) {
+ // Input validation.
+ if err := s3utils.CheckValidBucketName(bucketName); err != nil {
+ return nil, err
+ }
+ if err := s3utils.CheckValidObjectName(objectName); err != nil {
+ return nil, err
+ }
+
+ // Detect if snowball is server location we are talking to.
+ var snowball bool
+ if location, ok := c.bucketLocCache.Get(bucketName); ok {
+ if location == "snowball" {
+ snowball = true
+ }
+ }
+
+ var (
+ err error
+ httpReader io.ReadCloser
+ objectInfo ObjectInfo
+ totalRead int
+ )
+
+ // Create request channel.
+ reqCh := make(chan getRequest)
+ // Create response channel.
+ resCh := make(chan getResponse)
+ // Create done channel.
+ doneCh := make(chan struct{})
+
+ // This routine feeds partial object data as and when the caller reads.
+ go func() {
+ defer close(reqCh)
+ defer close(resCh)
+
+ // Used to verify if etag of object has changed since last read.
+ var etag string
+
+ // Loop through the incoming control messages and read data.
+ for {
+ select {
+ // When the done channel is closed exit our routine.
+ case <-doneCh:
+ // Close the http response body before returning.
+ // This ends the connection with the server.
+ if httpReader != nil {
+ httpReader.Close()
+ }
+ return
+
+ // Gather incoming request.
+ case req := <-reqCh:
+ // If this is the first request we may not need to do a getObject request yet.
+ if req.isFirstReq {
+ // First request is a Read/ReadAt.
+ if req.isReadOp {
+ // Differentiate between wanting the whole object and just a range.
+ if req.isReadAt {
+ // If this is a ReadAt request only get the specified range.
+ // Range is set with respect to the offset and length of the buffer requested.
+ // Do not set objectInfo from the first readAt request because it will not get
+ // the whole object.
+ opts.SetRange(req.Offset, req.Offset+int64(len(req.Buffer))-1)
+ } else if req.Offset > 0 {
+ opts.SetRange(req.Offset, 0)
+ }
+ httpReader, objectInfo, _, err = c.getObject(ctx, bucketName, objectName, opts)
+ if err != nil {
+ resCh <- getResponse{Error: err}
+ return
+ }
+ etag = objectInfo.ETag
+ // Read at least firstReq.Buffer bytes, if not we have
+ // reached our EOF.
+ size, err := readFull(httpReader, req.Buffer)
+ totalRead += size
+ if size > 0 && err == io.ErrUnexpectedEOF {
+ if int64(size) < objectInfo.Size {
+ // In situations when returned size
+ // is less than the expected content
+ // length set by the server, make sure
+ // we return io.ErrUnexpectedEOF
+ err = io.ErrUnexpectedEOF
+ } else {
+ // If an EOF happens after reading some but not
+ // all the bytes ReadFull returns ErrUnexpectedEOF
+ err = io.EOF
+ }
+ } else if size == 0 && err == io.EOF && objectInfo.Size > 0 {
+ // Special cases when server writes more data
+ // than the content-length, net/http response
+ // body returns an error, instead of converting
+ // it to io.EOF - return unexpected EOF.
+ err = io.ErrUnexpectedEOF
+ }
+ // Send back the first response.
+ resCh <- getResponse{
+ objectInfo: objectInfo,
+ Size: size,
+ Error: err,
+ didRead: true,
+ }
+ } else {
+ // First request is a Stat or Seek call.
+ // Only need to run a StatObject until an actual Read or ReadAt request comes through.
+
+ // Remove range header if already set, for stat Operations to get original file size.
+ delete(opts.headers, "Range")
+ objectInfo, err = c.statObject(ctx, bucketName, objectName, StatObjectOptions(opts))
+ if err != nil {
+ resCh <- getResponse{
+ Error: err,
+ }
+ // Exit the go-routine.
+ return
+ }
+ etag = objectInfo.ETag
+ // Send back the first response.
+ resCh <- getResponse{
+ objectInfo: objectInfo,
+ }
+ }
+ } else if req.settingObjectInfo { // Request is just to get objectInfo.
+ // Remove range header if already set, for stat Operations to get original file size.
+ delete(opts.headers, "Range")
+ // Check whether this is snowball
+ // if yes do not use If-Match feature
+ // it doesn't work.
+ if etag != "" && !snowball {
+ opts.SetMatchETag(etag)
+ }
+ objectInfo, err := c.statObject(ctx, bucketName, objectName, StatObjectOptions(opts))
+ if err != nil {
+ resCh <- getResponse{
+ Error: err,
+ }
+ // Exit the goroutine.
+ return
+ }
+ // Send back the objectInfo.
+ resCh <- getResponse{
+ objectInfo: objectInfo,
+ }
+ } else {
+ // Offset changes fetch the new object at an Offset.
+ // Because the httpReader may not be set by the first
+ // request if it was a stat or seek it must be checked
+ // if the object has been read or not to only initialize
+ // new ones when they haven't been already.
+ // All readAt requests are new requests.
+ if req.DidOffsetChange || !req.beenRead {
+ // Check whether this is snowball
+ // if yes do not use If-Match feature
+ // it doesn't work.
+ if etag != "" && !snowball {
+ opts.SetMatchETag(etag)
+ }
+ if httpReader != nil {
+ // Close previously opened http reader.
+ httpReader.Close()
+ }
+ // If this request is a readAt only get the specified range.
+ if req.isReadAt {
+ // Range is set with respect to the offset and length of the buffer requested.
+ opts.SetRange(req.Offset, req.Offset+int64(len(req.Buffer))-1)
+ } else if req.Offset > 0 { // Range is set with respect to the offset.
+ opts.SetRange(req.Offset, 0)
+ }
+ httpReader, objectInfo, _, err = c.getObject(ctx, bucketName, objectName, opts)
+ if err != nil {
+ resCh <- getResponse{
+ Error: err,
+ }
+ return
+ }
+ totalRead = 0
+ }
+
+ // Read at least req.Buffer bytes, if not we have
+ // reached our EOF.
+ size, err := readFull(httpReader, req.Buffer)
+ totalRead += size
+ if size > 0 && err == io.ErrUnexpectedEOF {
+ if int64(totalRead) < objectInfo.Size {
+ // In situations when returned size
+ // is less than the expected content
+ // length set by the server, make sure
+ // we return io.ErrUnexpectedEOF
+ err = io.ErrUnexpectedEOF
+ } else {
+ // If an EOF happens after reading some but not
+ // all the bytes ReadFull returns ErrUnexpectedEOF
+ err = io.EOF
+ }
+ } else if size == 0 && err == io.EOF && objectInfo.Size > 0 {
+ // Special cases when server writes more data
+ // than the content-length, net/http response
+ // body returns an error, instead of converting
+ // it to io.EOF - return unexpected EOF.
+ err = io.ErrUnexpectedEOF
+ }
+
+ // Reply back how much was read.
+ resCh <- getResponse{
+ Size: size,
+ Error: err,
+ didRead: true,
+ objectInfo: objectInfo,
+ }
+ }
+ }
+ }
+ }()
+
+ // Create a newObject through the information sent back by reqCh.
+ return newObject(reqCh, resCh, doneCh), nil
+}
+
+// get request message container to communicate with internal
+// go-routine.
+type getRequest struct {
+ Buffer []byte
+ Offset int64 // readAt offset.
+ DidOffsetChange bool // Tracks the offset changes for Seek requests.
+ beenRead bool // Determines if this is the first time an object is being read.
+ isReadAt bool // Determines if this request is a request to a specific range
+ isReadOp bool // Determines if this request is a Read or Read/At request.
+ isFirstReq bool // Determines if this request is the first time an object is being accessed.
+ settingObjectInfo bool // Determines if this request is to set the objectInfo of an object.
+}
+
+// get response message container to reply back for the request.
+type getResponse struct {
+ Size int
+ Error error
+ didRead bool // Lets subsequent calls know whether or not httpReader has been initiated.
+ objectInfo ObjectInfo // Used for the first request.
+}
+
+// Object represents an open object. It implements
+// Reader, ReaderAt, Seeker, Closer for a HTTP stream.
+type Object struct {
+ // Mutex.
+ mutex *sync.Mutex
+
+ // User allocated and defined.
+ reqCh chan<- getRequest
+ resCh <-chan getResponse
+ doneCh chan<- struct{}
+ currOffset int64
+ objectInfo ObjectInfo
+
+ // Ask lower level to initiate data fetching based on currOffset
+ seekData bool
+
+ // Keeps track of closed call.
+ isClosed bool
+
+ // Keeps track of if this is the first call.
+ isStarted bool
+
+ // Previous error saved for future calls.
+ prevErr error
+
+ // Keeps track of if this object has been read yet.
+ beenRead bool
+
+ // Keeps track of if objectInfo has been set yet.
+ objectInfoSet bool
+}
+
+// doGetRequest - sends and blocks on the firstReqCh and reqCh of an object.
+// Returns back the size of the buffer read, if anything was read, as well
+// as any error encountered. For all first requests sent on the object
+// it is also responsible for sending back the objectInfo.
+func (o *Object) doGetRequest(request getRequest) (getResponse, error) {
+ o.reqCh <- request
+ response := <-o.resCh
+
+ // Return any error to the top level.
+ if response.Error != nil {
+ return response, response.Error
+ }
+
+ // This was the first request.
+ if !o.isStarted {
+ // The object has been operated on.
+ o.isStarted = true
+ }
+ // Set the objectInfo if the request was not readAt
+ // and it hasn't been set before.
+ if !o.objectInfoSet && !request.isReadAt {
+ o.objectInfo = response.objectInfo
+ o.objectInfoSet = true
+ }
+ // Set beenRead only if it has not been set before.
+ if !o.beenRead {
+ o.beenRead = response.didRead
+ }
+ // Data are ready on the wire, no need to reinitiate connection in lower level
+ o.seekData = false
+
+ return response, nil
+}
+
+// setOffset - handles the setting of offsets for
+// Read/ReadAt/Seek requests.
+func (o *Object) setOffset(bytesRead int64) error {
+ // Update the currentOffset.
+ o.currOffset += bytesRead
+
+ if o.objectInfo.Size > -1 && o.currOffset >= o.objectInfo.Size {
+ return io.EOF
+ }
+ return nil
+}
+
+// Read reads up to len(b) bytes into b. It returns the number of
+// bytes read (0 <= n <= len(b)) and any error encountered. Returns
+// io.EOF upon end of file.
+func (o *Object) Read(b []byte) (n int, err error) {
+ if o == nil {
+ return 0, errInvalidArgument("Object is nil")
+ }
+
+ // Locking.
+ o.mutex.Lock()
+ defer o.mutex.Unlock()
+
+ // prevErr is previous error saved from previous operation.
+ if o.prevErr != nil || o.isClosed {
+ return 0, o.prevErr
+ }
+
+ // Create a new request.
+ readReq := getRequest{
+ isReadOp: true,
+ beenRead: o.beenRead,
+ Buffer: b,
+ }
+
+ // Alert that this is the first request.
+ if !o.isStarted {
+ readReq.isFirstReq = true
+ }
+
+ // Ask to establish a new data fetch routine based on seekData flag
+ readReq.DidOffsetChange = o.seekData
+ readReq.Offset = o.currOffset
+
+ // Send and receive from the first request.
+ response, err := o.doGetRequest(readReq)
+ if err != nil && err != io.EOF {
+ // Save the error for future calls.
+ o.prevErr = err
+ return response.Size, err
+ }
+
+ // Bytes read.
+ bytesRead := int64(response.Size)
+
+ // Set the new offset.
+ oerr := o.setOffset(bytesRead)
+ if oerr != nil {
+ // Save the error for future calls.
+ o.prevErr = oerr
+ return response.Size, oerr
+ }
+
+ // Return the response.
+ return response.Size, err
+}
+
+// Stat returns the ObjectInfo structure describing Object.
+func (o *Object) Stat() (ObjectInfo, error) {
+ if o == nil {
+ return ObjectInfo{}, errInvalidArgument("Object is nil")
+ }
+ // Locking.
+ o.mutex.Lock()
+ defer o.mutex.Unlock()
+
+ if o.prevErr != nil && o.prevErr != io.EOF || o.isClosed {
+ return ObjectInfo{}, o.prevErr
+ }
+
+ // This is the first request.
+ if !o.isStarted || !o.objectInfoSet {
+ // Send the request and get the response.
+ _, err := o.doGetRequest(getRequest{
+ isFirstReq: !o.isStarted,
+ settingObjectInfo: !o.objectInfoSet,
+ })
+ if err != nil {
+ o.prevErr = err
+ return ObjectInfo{}, err
+ }
+ }
+
+ return o.objectInfo, nil
+}
+
+// ReadAt reads len(b) bytes from the File starting at byte offset
+// off. It returns the number of bytes read and the error, if any.
+// ReadAt always returns a non-nil error when n < len(b). At end of
+// file, that error is io.EOF.
+func (o *Object) ReadAt(b []byte, offset int64) (n int, err error) {
+ if o == nil {
+ return 0, errInvalidArgument("Object is nil")
+ }
+
+ // Locking.
+ o.mutex.Lock()
+ defer o.mutex.Unlock()
+
+ // prevErr is error which was saved in previous operation.
+ if o.prevErr != nil && o.prevErr != io.EOF || o.isClosed {
+ return 0, o.prevErr
+ }
+
+ // Set the current offset to ReadAt offset, because the current offset will be shifted at the end of this method.
+ o.currOffset = offset
+
+ // Can only compare offsets to size when size has been set.
+ if o.objectInfoSet {
+ // If offset is negative than we return io.EOF.
+ // If offset is greater than or equal to object size we return io.EOF.
+ if (o.objectInfo.Size > -1 && offset >= o.objectInfo.Size) || offset < 0 {
+ return 0, io.EOF
+ }
+ }
+
+ // Create the new readAt request.
+ readAtReq := getRequest{
+ isReadOp: true,
+ isReadAt: true,
+ DidOffsetChange: true, // Offset always changes.
+ beenRead: o.beenRead, // Set if this is the first request to try and read.
+ Offset: offset, // Set the offset.
+ Buffer: b,
+ }
+
+ // Alert that this is the first request.
+ if !o.isStarted {
+ readAtReq.isFirstReq = true
+ }
+
+ // Send and receive from the first request.
+ response, err := o.doGetRequest(readAtReq)
+ if err != nil && err != io.EOF {
+ // Save the error.
+ o.prevErr = err
+ return response.Size, err
+ }
+ // Bytes read.
+ bytesRead := int64(response.Size)
+ // There is no valid objectInfo yet
+ // to compare against for EOF.
+ if !o.objectInfoSet {
+ // Update the currentOffset.
+ o.currOffset += bytesRead
+ } else {
+ // If this was not the first request update
+ // the offsets and compare against objectInfo
+ // for EOF.
+ oerr := o.setOffset(bytesRead)
+ if oerr != nil {
+ o.prevErr = oerr
+ return response.Size, oerr
+ }
+ }
+ return response.Size, err
+}
+
+// Seek sets the offset for the next Read or Write to offset,
+// interpreted according to whence: 0 means relative to the
+// origin of the file, 1 means relative to the current offset,
+// and 2 means relative to the end.
+// Seek returns the new offset and an error, if any.
+//
+// Seeking to a negative offset is an error. Seeking to any positive
+// offset is legal, subsequent io operations succeed until the
+// underlying object is not closed.
+func (o *Object) Seek(offset int64, whence int) (n int64, err error) {
+ if o == nil {
+ return 0, errInvalidArgument("Object is nil")
+ }
+
+ // Locking.
+ o.mutex.Lock()
+ defer o.mutex.Unlock()
+
+ // At EOF seeking is legal allow only io.EOF, for any other errors we return.
+ if o.prevErr != nil && o.prevErr != io.EOF {
+ return 0, o.prevErr
+ }
+
+ // Negative offset is valid for whence of '2'.
+ if offset < 0 && whence != 2 {
+ return 0, errInvalidArgument(fmt.Sprintf("Negative position not allowed for %d", whence))
+ }
+
+ // This is the first request. So before anything else
+ // get the ObjectInfo.
+ if !o.isStarted || !o.objectInfoSet {
+ // Create the new Seek request.
+ seekReq := getRequest{
+ isReadOp: false,
+ Offset: offset,
+ isFirstReq: true,
+ }
+ // Send and receive from the seek request.
+ _, err := o.doGetRequest(seekReq)
+ if err != nil {
+ // Save the error.
+ o.prevErr = err
+ return 0, err
+ }
+ }
+
+ // Switch through whence.
+ switch whence {
+ default:
+ return 0, errInvalidArgument(fmt.Sprintf("Invalid whence %d", whence))
+ case 0:
+ if o.objectInfo.Size > -1 && offset > o.objectInfo.Size {
+ return 0, io.EOF
+ }
+ o.currOffset = offset
+ case 1:
+ if o.objectInfo.Size > -1 && o.currOffset+offset > o.objectInfo.Size {
+ return 0, io.EOF
+ }
+ o.currOffset += offset
+ case 2:
+ // If we don't know the object size return an error for io.SeekEnd
+ if o.objectInfo.Size < 0 {
+ return 0, errInvalidArgument("Whence END is not supported when the object size is unknown")
+ }
+ // Seeking to positive offset is valid for whence '2', but
+ // since we are backing a Reader we have reached 'EOF' if
+ // offset is positive.
+ if offset > 0 {
+ return 0, io.EOF
+ }
+ // Seeking to negative position not allowed for whence.
+ if o.objectInfo.Size+offset < 0 {
+ return 0, errInvalidArgument(fmt.Sprintf("Seeking at negative offset not allowed for %d", whence))
+ }
+ o.currOffset = o.objectInfo.Size + offset
+ }
+ // Reset the saved error since we successfully seeked, let the Read
+ // and ReadAt decide.
+ if o.prevErr == io.EOF {
+ o.prevErr = nil
+ }
+
+ // Ask lower level to fetch again from source
+ o.seekData = true
+
+ // Return the effective offset.
+ return o.currOffset, nil
+}
+
+// Close - The behavior of Close after the first call returns error
+// for subsequent Close() calls.
+func (o *Object) Close() (err error) {
+ if o == nil {
+ return errInvalidArgument("Object is nil")
+ }
+ // Locking.
+ o.mutex.Lock()
+ defer o.mutex.Unlock()
+
+ // if already closed return an error.
+ if o.isClosed {
+ return o.prevErr
+ }
+
+ // Close successfully.
+ close(o.doneCh)
+
+ // Save for future operations.
+ errMsg := "Object is already closed. Bad file descriptor."
+ o.prevErr = errors.New(errMsg)
+ // Save here that we closed done channel successfully.
+ o.isClosed = true
+ return nil
+}
+
+// newObject instantiates a new *minio.Object*
+// ObjectInfo will be set by setObjectInfo
+func newObject(reqCh chan<- getRequest, resCh <-chan getResponse, doneCh chan<- struct{}) *Object {
+ return &Object{
+ mutex: &sync.Mutex{},
+ reqCh: reqCh,
+ resCh: resCh,
+ doneCh: doneCh,
+ }
+}
+
+// getObject - retrieve object from Object Storage.
+//
+// Additionally this function also takes range arguments to download the specified
+// range bytes of an object. Setting offset and length = 0 will download the full object.
+//
+// For more information about the HTTP Range header.
+// go to http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.
+func (c Client) getObject(ctx context.Context, bucketName, objectName string, opts GetObjectOptions) (io.ReadCloser, ObjectInfo, http.Header, error) {
+ // Validate input arguments.
+ if err := s3utils.CheckValidBucketName(bucketName); err != nil {
+ return nil, ObjectInfo{}, nil, err
+ }
+ if err := s3utils.CheckValidObjectName(objectName); err != nil {
+ return nil, ObjectInfo{}, nil, err
+ }
+
+ urlValues := make(url.Values)
+ if opts.VersionID != "" {
+ urlValues.Set("versionId", opts.VersionID)
+ }
+
+ // Execute GET on objectName.
+ resp, err := c.executeMethod(ctx, http.MethodGet, requestMetadata{
+ bucketName: bucketName,
+ objectName: objectName,
+ queryValues: urlValues,
+ customHeader: opts.Header(),
+ contentSHA256Hex: emptySHA256Hex,
+ })
+ if err != nil {
+ return nil, ObjectInfo{}, nil, err
+ }
+ if resp != nil {
+ if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusPartialContent {
+ return nil, ObjectInfo{}, nil, httpRespToErrorResponse(resp, bucketName, objectName)
+ }
+ }
+
+ objectStat, err := ToObjectInfo(bucketName, objectName, resp.Header)
+ if err != nil {
+ closeResponse(resp)
+ return nil, ObjectInfo{}, nil, err
+ }
+
+ // do not close body here, caller will close
+ return resp.Body, objectStat, resp.Header, nil
+}